docs: def pretty_repr(instance):
      """
      A function assignable to the ``__repr__`` dunder method, so that
      the ``prettyprinter`` definition for the type is used to provide
      repr output. Usage:
  
      .. code:: python
  
          from prettyprinter import pretty_repr
  
          class MyClass:
              __repr__ = pretty_repr
  
      """
  
      instance_type = type(instance)
      if not is_registered(
          instance_type,
          check_superclasses=True,
          check_deferred=True,
          register_deferred=True
      ):
          warnings.warn(
              "pretty_repr is assigned as the __repr__ method of "
              "'{}'. However, no pretty printer is registered for that type, "
              "its superclasses or its subclasses. Falling back to the default "
              "repr implementation. To fix this warning, register a pretty "
              "printer using prettyprinter.register_pretty.".format(
                  instance_type.__qualname__
              ),
              UserWarning
          )
          return object.__repr__(instance)
  
      return pformat(instance)